The invention relates to a process for the production of 1,5-naphthalenediamine by the reaction of ortho-nitrotoluene with an acrylic acid derivative, and to the intermediate products 4-(2-nitrophenyl)butyronitrile, 5-nitro-3,4-dihydro-1(2H)-naphthylimine, 5-nitroso-1-naphthylamine, 5-nitro-1-naphthylamine, 4-(2-aminophenyl)butyronitrile, 4-(2-nitrophenyl)ethyl butyrate, 4-(2-nitrophenyl)butyl butyrate, 4-(2-nitrophenyl)-butyramide and 5-amino-3,4-dihydro-1(2H)-naphthalene imine obtainable during the process.
Various processes for the production of 1,5-naphthalenediamine are already known in the literature. In general, the preparation of 1,5-naphthalenediamine starts from naphthalene which is suitably substituted. Thus, in JP-A2-07 278 066, the synthesis of 1,5-naphthalenediamine via an amine-bromine exchange on 1,5-bromoamino-naphthalene is described. The required educt is produced by bromination of 1-nitronaphthalene in this process.
In JP-A2-04 154 745, JP-A2-56 059 738 and DE-A1-2 523 351, the synthesis of 1,5-naphthalenediamine in combination with 1,8-naphthalenediamine by the reduction of a mixture of 1,5- and 1,8-dinitronaphthalene is described. In DE-C1-3 840 618, the synthesis of 1,5-naphthalenediamine by alkaline hydrolysis of disodium naphthalene-1,5-disulfonate and subsequent reaction with ammonia is described.
All these processes have the disadvantage that the product, or an intermediate produced during the process, is obtained as a mixture of isomers containing other isomers in addition to the 1,5 isomer, which have to be separated off. In addition, the process described in DE-C1-3 840 618 in particular takes place under very severe and corrosive reaction conditions.
The object of the present invention is therefore to provide a simple process for the production of 1,5-naphthalenediamine, by which 1,5-naphthalenediamine can be produced in just a few steps, starting from basic chemicals, without other isomers forming in significant quantities and having to be separated off.
A process has now been found, by which 1,5-naphthalenediamine can be prepared simply, in just a few steps and largely as a pure isomer, starting from ortho-nitrotoluene and acrylic acid derivatives, such as e.g. acrylonitrile, two inexpensive basic chemicals.
The object is achieved according to the invention by a process for the production of 1,5-naphthalenediamine containing a step in which ortho-nitrotoluene is reacted with an acrylic acid derivative.
Preferred acrylic acid derivatives are acrylic acid esters, such as e.g. methyl acrylate and ethyl acrylate, acrylamide and acrylonitrile.
The object is achieved according to the invention in particular by a process for the production of 1,5-naphthalenediamine containing a step in which ortho-nitrotoluene is reacted with acrylonitrile to give 4-(2-nitrophenyl)butyronitrile.
In a first preferred embodiment, the process for the production of 1,5-naphthalene-diamine contains the following steps:
a) reaction of ortho-nitrotoluene with acrylonitrile to give 4-(2-nitrophenyl)-butyronitrile,
b) cyclisation of the 4-(2-nitrophenyl)butyronitrile formed in step a) to the nitro imine and/or nitro enamine,
c) aromatisation of the nitro imine and/or nitro enamine formed in step b) to give 5-nitro-1-naphthylamine and/or 5-nitroso-1-naphthylamine,
d) hydrogenation of the 5-nitro-1-naphthylamine and/or 5-nitroso-1-naphthylamine formed in step c) to give 1,5-naphthalenediamine.
4-(2-Nitrophenyl)butyronitrile is produced from ortho-nitrotoluene and acrylonitrile preferably at temperatures of xe2x88x9210xc2x0 C. to 100xc2x0 C. It is particularly preferred to operate at 20xc2x0 C. to 75xc2x0 C., especially preferably at temperatures of 30xc2x0 C. to 60xc2x0 C.
The reaction is performed with base catalysis. Oxides, hydroxides and carbonates of lithium, sodium, potassium, rubidium, caesium, magnesium, calcium, strontium, barium or aluminium, and mixtures thereof, can be used as bases. Sodium hydroxide and potassium hydroxide are particularly suitable. In a preferred embodiment, the aqueous solutions are used in combination with a phase transfer catalyst. These phase transfer catalysts are e.g. quaternary ammonium salts. Suitable ammonium compounds are tetraalkylammonium halides and hydrogen sulfates, such as tributylmethyl-ammonium chloride, trioctylammonium chloride, tetrabutylammonium chloride or tetrabutylammonium hydrogen sulfate. The use of appropriate tetraalkyl- or tetraarylphosphonium salts, such as tetramethylphosphonium bromide and tetraphenyl-phosphonium bromide is also suitable, as is the use of solubility promoters, such as polyethylene glycol dimethyl ethers.
In principle, water and all organic solvents that are stable in bases are suitable as the solvents. Aromatic solvents, such as benzene, toluene, xylene, chlorobenzene, nitrobenzene or nitrotoluene, and also dimethyl sulfoxide, dimethyl formamide and aliphatic hydrocarbons, such as ligroin, cyclohexane, pentane, hexane, heptane or octane, are preferably used.
ortho-Nitrotoluene is particularly preferably used as educt and, at the same time, as solvent, and in an excess of ortho-nitrotoluene of 1 to 40 equivalents, especially 5 to 20 equivalents, based on acrylonitrile.
The cyclisation of 4-(2-nitrophenyl)butyronitrile to 5-nitro-3,4-dihydro-1-naphthylamine or the tautomeric 5-nitro-3,4-dihydro-1(2H)-naphthylimine is performed in substance or in an inert solvent in the presence of strong acids. Suitable solvents are linear, branched or cyclic aliphatic hydrocarbons, such as ligroin or cyclohexane, pentane, hexane, heptane, octane and aromatic solvents such as nitrotoluene. It is preferred to operate in substance or in ortho-nitrotoluene.
Suitable acids are strong Lewis or Bronsted acids, such as e.g. aluminium chloride, boron trifluoride, sulfuric acid, phosphoric acid, polyphosphoric acid, phosphorus pentoxide, methanesulfonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid or mixtures of antimony pentafluoride and fluorosulfuric acid. Mixtures of the acids can also be used.
The acid is generally used in 0.1 to 100 mole equivalents, based on 4-(2-nitrophenyl)-butyronitrile. Preferably, 0.5 to 20 equivalents are used, particularly preferably 1 to 10 equivalents.
The reaction is generally carried out at temperatures of 0xc2x0 C. to 200xc2x0 C., preferably between 40xc2x0 C. and 150xc2x0 C., particularly preferably between 60xc2x0 C. and 110xc2x0 C.
The nitro imine and/or nitro enamine formed in step b), which is sensitive to hydrolysis, is preferably first converted to the nitroketone 5-nitro-3,4-dihydro-1(2H)-naphthalenone, e.g. by hydrolysis, and the nitroketone is isolated. The isolation takes place e.g. by phase separation.
The nitroketone is then converted back to the nitro imine and/or nitro enamine in step c) by reaction with ammonia, preferably in the presence of ammonium salts such as ammonium chloride, and then aromatised. The aromatisation then preferably takes place in ammonia as the solvent.
The aromatisation or dehydrogenation of the nitro enamine 5-nitro-3,4-dihydro-1-naphthylamine or of the nitro imine 5-nitro-3,4-dihydro-1(2H)-naphthylimine to 5-nitro-1-naphthylamine or 5-nitroso-1-naphthylamine or a mixture of the compounds is carried out, e.g. in an inert solvent, in the presence of a catalyst. In addition to the dehydrogenated product 5-nitro-1-naphthylamine, 5-nitroso-1-naphthylamine formally resulting from symproportionation can also be produced in the process. 1,5-Naphthalenediamine is also formed in traces. The products can be further processed in any mixing ratios. Suitable solvents are ammonia and linear, branched or cyclic aliphatic hydrocarbons such as ligroin or cyclohexane, and also acetonitrile and aromatic solvents such as benzene, toluene, xylene, nitrobenzene, nitrotoluene or chlorobenzene. The aromatisation can also be performed in the absence of a solvent.
Suitable catalysts are dehydrogenation catalysts, which are described in the literature (Rxc3x6mpp Lexikon Chemie; Georg Thieme Verlag, Stuttgart, 10th edition 1997, p. 891, chapter xe2x80x9cDehydrierungxe2x80x9d, 1st section; Ullmann""s Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 5th edition 1989, vol. A13, chapter xe2x80x9cHydrogenation and Dehydrogenationxe2x80x9d, sub-chapter 2, xe2x80x9cDehydrogenationxe2x80x9d, p. 494-497). These include the metals of groups 8-10 of the periodic table (G. J. Leigh [editor], Nomenclature of Inorganic Chemistry, Recommendations 1990, Blackwell Scientific Publications, Oxford, Chapter I-3.8.1 xe2x80x9cGroups of Elements in the Periodic Table and their Subdivision, p. 41-43), especially platinum, palladium, ruthenium and iridium, iron, cobalt, nickel and combinations thereof. The metals can also be used together with other metals, such as lanthanum, scandium, vanadium, chromium, molybdenum, tungsten, manganese, tin, zinc, copper, silver or indium. The above metals can be present as pure elements, as oxides, sulfides, halides, carbides or nitrides or can be used in combination with organic ligands. Suitable as ligands are hydrocarbon compounds with donor groups, such as e.g. amines, nitrites, phosphines, thiols, thioethers, alcohols, ethers or carboxylic acids. The catalysts are optionally applied to a support material. Suitable support materials are activated charcoal, aluminium oxide, silicon dioxide, zirconium oxide, zinc oxide or zeolites.
Work is optionally performed in the presence of an oxidising agent such as oxygen or air. The reaction is generally carried out at temperatures of 50xc2x0 C. to 250xc2x0 C., preferably at 100xc2x0 C. to 200xc2x0 C.
The reduction of the nitro group to the product 1,5-naphthalenediamine takes place by hydrogenation in the presence of suitable hydrogenation catalysts.
Practically all heterogeneous catalysts that are known as hydrogenation catalysts are suitable as hydrogenation catalysts for the process according to the invention (Rxc3x6mpp Lexikon Chemie; Georg Thieme Verlag, Stuttgart, 10th edition 1997, p. 1831, chapter xe2x80x9cHydrierungxe2x80x9d; Ullmann""s Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 5th edition 1989, vol. A13, chapter xe2x80x9cHydrogenation and Dehydrogenationxe2x80x9d, sub-chapter 1.2 xe2x80x9cCatalystsxe2x80x9d, p. 488). Preferred catalysts are the metals of groups 8-10 of the periodic table (G. J. Leigh [editor], Nomenclature of Inorganic Chemistry, Recommendations 1990, Blackwell Scientific Publications, Oxford, Chapter I-3.8.1 xe2x80x9cGroups of Elements in the Periodic Table and their Subdivision, p. 41-43), copper or chromium on a suitable support with a metal content of 0.01 to 50 wt. %, preferably 0.1 to 20 wt. %, based on the total weight of the catalyst. Catalysts containing one or more of the above-mentioned metals can also be used. Preferred metals are, in particular, platinum, palladium and rhodium, platinum and palladium being particularly preferred. Other preferred catalysts are Raney nickel and supported nickel catalysts. The above-mentioned metals or their compounds can also be used in pure form as a solid. Palladium black and platinum black can be mentioned as examples of a metal in pure form.
The catalysts can be used in batchwise process variants in quantities of 0.01 to 50 wt. %, based on 5-nitro- or 5-nitroso-1-naphthylamine used, preferably in quantities of 0.01 to 20 wt. %, particularly preferably in quantities of 0.01 to 10 wt. %. When the reaction is carried out continuously, for example in a stirred vessel with powdered catalyst or in the trickle phase on a fixed bed catalyst, loads of 0.01 to 500 g, preferably 0.1 to 200 g, particularly preferably 1 to 100 g of 5-nitro- or 5-nitroso-1-naphthylamine per g catalyst per hour can be set.
The reaction temperatures are generally xe2x88x9220xc2x0 C. to 150xc2x0 C., particularly xe2x88x9210xc2x0 C. to 80xc2x0 C.; the hydrogen pressure is generally 0.1 to 150 bar, particularly 0.5 to 70 bar, especially preferably 1 to 50 bar.
The same catalyst is preferably used for the aromatisation and the subsequent hydrogenation, it being possible for the two steps to be performed in one reaction vessel.
All the reaction steps in this preferred embodiment of the process can be carried out continuously or batchwise, e.g. in stirred vessel reactors or tubular reactors.
In a second preferred embodiment, the process for the production of 1,5-naphthalenediamine contains the steps
a) reaction of ortho-nitrotoluene with acrylonitrile to give 4-(2-nitrophenyl)-butyronitrile,
b) reduction of the 4-(2-nitrophenyl)butyronitrile formed in step a) to give 4-(2-aminophenyl)butyronitrile,
c) cyclisation of the 4-(2-aminophenyl)butyronitrile formed in step b) to the amino imine and/or amino enamine,
d) aromatisation of the amino imine and/or amino enamine formed in step c) to give 1,5-naphthalenediamine.
4-(2-Nitrophenyl)butyronitrile is prepared from ortho-nitrotoluene and acrylonitrile as in step a) of the first preferred embodiment.
This compound is then reduced to 4-(2-aminophenyl)butyronitrile. The transformation can be performed by hydrogenation in the presence of a hydrogenation catalyst. Practically all heterogeneous catalysts that are known as hydrogenation catalysts are suitable as hydrogenation catalysts for the process according to the invention (Rxc3x6mpp Lexikon Chemie; Georg Thieme Verlag, Stuttgart, 10th edition 1997, p. 1831, chapter xe2x80x9cHydrierungxe2x80x9d; Ullmann""s Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 5th edition 1989, vol. A13, chapter xe2x80x9cHydrogenation and Dehydrogenationxe2x80x9d, sub-chapter 1.2 xe2x80x9cCatalystsxe2x80x9d, p. 488). Preferred catalysts are the metals of groups 8-10 of the periodic table (G. J. Leigh [editor], Nomenclature of Inorganic Chemistry, Recommendations 1990, Blackwell Scientific Publications, Oxford, Chapter I-3.8.1 xe2x80x9cGroups of Elements in the Periodic Table and their Subdivision, p. 41-43), copper or chromium on a suitable support with a metal content of 0.01 to 50 wt. %, preferably 0.1 to 20 wt. %, based on the total weight of the catalyst. Catalysts containing one or more of the above-mentioned metals can also be used. Preferred metals are, in particular, platinum, palladium and rhodium, platinum and palladium being particularly preferred. Other preferred catalysts are Raney nickel and supported nickel catalysts. The above-mentioned metals or their compounds can also be used in pure form as a solid. Palladium black and platinum black can be mentioned as examples of a metal in pure form.
In another embodiment, the nitro group can be reduced by reaction with metal hydrides, optionally with the addition of additives, or by reaction with base metals such as iron.
Preferred metal hydrides are sodium borohydride, potassium borohydride, lithium borohydride, sodium cyanoborohydride, lithium cyanoborohydride, lithium aluminium hydride and diisobutylaluminium hydride. Suitable additives are nickel salts, tellurium compounds and antimony compounds.
Preferred base metals for the reaction under acid conditions are iron, zinc, magnesium, aluminium and tin, iron and zinc being particularly preferred. Suitable solvents for this purpose are water or alcohols or mixtures of alcohols acidified with acids such as acetic acid, hydrochloric acid, sulfuric acid or ammonium chloride. Suitable alcohols are methanol, ethanol, n-propanol, isopropanol, n-butanol, sec.-butanol, tert.-butanol or cyclohexanol. Methanol and ethanol are particularly preferred.
The cyclisation to 5-amino-3,4-dihydro-1-naphthylamine or the imine tautomer 5-amino-3,4-dihydro-1(2H)-naphthylimine is performed in the same way as the cyclisation of the nitro compound (step b in the first preferred embodiment). However, owing to the basicity of the amino group in 4-(2-aminophenyl)butyronitrile, at least one mole equivalent of acid (based on 4-(2-aminophenyl)butyronitrile) must also be added. Preferably, 1.5 to 21 equivalents of acid are used, particularly preferably 1.5 to 11 equivalents.
The reaction is carried out in substance or in an inert solvent in the presence of strong acids. Suitable solvents are linear, branched or cyclic aliphatic hydrocarbons, such as ligroin or cyclohexane, pentane, hexane, heptane, octane and aromatic solvents such as nitrotoluene. It is preferred to work in substance or in ortho-nitrotoluene.
Suitable acids are strong Lewis or Bronsted acids, such as e.g. aluminium chloride, boron trifluoride, sulfuric acid, phosphoric acid, polyphosphoric acid, phosphorus pentoxide, methanesulfonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid or mixtures of antimony pentafluoride and fluorosulfuric acid. Mixtures of the acids can also be used.
The reaction is generally carried out at temperatures of 0xc2x0 C. to 150xc2x0 C., preferably between 60xc2x0 C. and 110xc2x0 C.
After the cyclisation, the reaction mixture is conventionally neutralised. This is achieved e.g. by adding sodium hydroxide solution.
The amino imine and/or amino enamine formed in step c) is preferably first converted to the aminoketone 5-amino-3,4-dihydro-1(2H)-naphthalenone, e.g. by hydrolysis, and the aminoketone is isolated. The isolation takes place e.g. by phase separation. The aminoketone is then converted back to the amino imine and/or amino enamine in step d) by reaction with ammonia, preferably in the presence of ammonium chloride, and then aromatised. The aromatisation then preferably takes place in ammonia.
The aromatisation of 5-amino-3,4-dihydro-1-naphthylamine or the imine tautomer 5-amino-3,4-dihydro-1(2H)-naphthylimine to 1,5-naphthalenediamine is performed in the same way as the aromatisation of the nitro compounds 5-nitro-3,4-dihydro-1-naphthyl-amine or 5-nitro-3,4-dihydro-1(2H)-naphthylimine (step c) of the first preferred embodiment).
The reaction is carried out in an inert solvent in the presence of a catalyst. Suitable solvents are ammonia and linear, branched or cyclic aliphatic hydrocarbons, such as ligroin or cyclohexane, and also acetonitrile and aromatic solvents such as benzene, toluene, xylene, nitrobenzene, nitrotoluene or chlorobenzene.
Suitable catalysts are dehydrogenation catalysts, which are described in the literature (Rxc3x6mpp Lexikon Chemie; Georg Thieme Verlag, Stuttgart, 10th edition 1997, p. 891, chapter xe2x80x9cDehydrierungxe2x80x9d, 1st section; Ullmann""s Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 5th edition 1989, vol. A13, chapter xe2x80x9cHydrogenation and Dehydrogenationxe2x80x9d, sub-chapter 2, xe2x80x9cDehydrogenationxe2x80x9d, p. 494-497). These include the metals of groups 8-10 of the periodic table (G. J. Leigh [editor], Nomenclature of Inorganic Chemistry, Recommendations 1990, Blackwell Scientific Publications, Oxford, Chapter I-3.8.1 xe2x80x9cGroups of Elements in the Periodic Table and their Subdivision, p. 41-43), especially platinum, palladium, ruthenium and iridium, iron, cobalt, nickel and combinations thereof. The metals can also be used together with other metals, such as lanthanum, scandium, vanadium, chromium, molybdenum, tungsten, manganese, tin, zinc, copper, silver or indium. The above metals can be present as pure elements, as oxides, sulfides, halides, carbides or nitrides or can be used in combination with organic ligands. Suitable as ligands are hydrocarbon compounds with donor groups such as e.g. amines, nitrites, phosphines, thiols, thioethers, alcohols, ethers or carboxylic acids. The catalysts are optionally applied to a support material. Suitable support materials are activated charcoal, aluminium oxide, silicon dioxide, zirconium oxide, zinc oxide or zeolites.
Work is optionally performed in the presence of an oxidising agent such as oxygen or air.
The reaction is generally carried out at temperatures of 50xc2x0 C. to 250xc2x0 C., preferably at 100xc2x0 C. to 200xc2x0 C.
All the reaction steps in this preferred embodiment of the process can be performed continuously or batchwise, e.g. in stirred vessel reactors or tubular reactors.
In a third preferred embodiment, the process for the production of 1,5-naphthalene-diamine contains the steps
a) reaction of ortho-nitrotoluene with acrylonitrile to give 4-(2-nitrophenyl)-butyronitrile,
b) cyclisation of the 4-(2-nitrophenyl)butyronitrile formed in step a) to the nitro imine and/or nitro enamine,
c) reduction of the nitro imine and/or nitro enamine formed in step b) to give the amino imine and/or amino enamine,
d) aromatisation of the amino imine and/or amino enamine formed in step c) to give 1,5-naphthalenediamine. 4-(2-Nitrophenyl)butyronitrile is prepared from ortho-nitrotoluene and acrylonitrile in the same way as in step a) of the first preferred embodiment.
This compound is then cyclised to give 5-nitro-3,4-dihydro-1-naphthylamine or the tautomeric 5-nitro-3,4-dihydro-1(2H)-naphthylimine in the same way as in step b) of the first preferred embodiment.
The compound 5-nitro-3,4-dihydro-1-naphthylamine or the tautomeric 5-nitro-3,4-dihydro-1(2H)-naphthylimine is now reduced to give 5-amino-3,4-dihydro-1-naphthyl-amine or the tautomeric 5-amino-3,4-dihydro-1(2H)-naphthylimine.
The transformation can be performed by hydrogenation in the presence of a hydrogenation catalyst. Practically all heterogeneous catalysts that are known as hydrogenation catalysts are suitable as hydrogenation catalysts for the process according to the invention (Rxc3x6mpp Lexikon Chemie; Georg Theme Verlag, Stuttgart, 10th edition 1997, p. 1831, chapter xe2x80x9cHydrierungxe2x80x9d; Ullmann""s Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 5th edition 1989, vol. A13, chapter xe2x80x9cHydrogenation and Dehydrogenationxe2x80x9d, sub-chapter 1.2 xe2x80x9cCatalystsxe2x80x9d, p. 488). Preferred catalysts are the metals of groups 8-10 of the periodic table (G. J. Leigh [editor], Nomenclature of Inorganic Chemistry, Recommendations 1990, Blackwell Scientific Publications, Oxford, Chapter I-3.8.1 xe2x80x9cGroups of Elements in the Periodic Table and their Subdivision, p. 41-43), copper or chromium on a suitable support with, a metal content of 0.01 to 50 wt. %, preferably 0.1 to 20 wt. %, based on the total weight of the catalyst. Catalysts containing one or more of the above-mentioned metals can also be used. Preferred metals are, in particular, platinum, palladium and rhodium, platinum and palladium being particularly preferred. Other preferred catalysts are Raney nickel and supported nickel catalysts. The above-mentioned metals or their compounds can also be used in pure form as a solid. Palladium black and platinum black can be mentioned as examples of a metal in pure form.
The final aromatisation of 5-amino-3,4-dihydro-1-naphthylamine or the tautomeric 5-amino-3,4-dihydro-1(2H)-naphthylimine to 1,5-naphthalenediamine is performed in the same way as in step d) of the second preferred embodiment.
All the reaction steps in this preferred embodiment of the process can be carried out continuously or batchwise, e.g. in stirred vessel reactors or tubular reactors.
In a fourth preferred embodiment the process for the production of 1,5-naphthalenediamine contains the steps:
a) reaction of ortho-nitrotoluene with acrylonitrile to give 4-(2-nitrophenyl)-butyronitrile,
b) cyclisation of the 4-(2-nitrophenyl)butyronitrile formed in step a) to the nitro imine and/or nitro enamine, conversion to the nitroketone 5-nitro-3,4-dihydro-1(2H)-naphthalenone, and isolation of the nitroketone,
c) reduction of the nitroketone formed in step b) to give the aminoketone 5-amino-3,4-dihydro-1(2H)-naphthalenone,
d) conversion of the aminoketone formed in step c) to the amino imine and/or amino enamine and aromatisation to give 1,5-naphthalenediamine.
4-(2-Nitrophenyl)butyronitrile is prepared from ortho-nitrotoluene and acrylonitrile in the same way as in step a) of the first preferred embodiment.
4-(2-Nitrophenyl)butyronitrile is then cyclised to 5-nitro-3,4-dihydro-1-naphthylamine or the tautomeric 5-nitro-3,4-dihydro-1(2H)-naphthylimine as in step b) of the first preferred embodiment. The 5-nitro-3,4-dihydro-1-naphthylamine and/or 5-nitro-3,4-dihydro-1(2H)-naphthylimine is then converted to the nitroketone 5-nitro-3,4-dihydro-1(2H)-naphthalenone, e.g. by hydrolysis, and the nitroketone is isolated. The isolation of the nitroketone takes place e.g. by phase separation.
The compound 5-nitro-3,4-dihydro-1(2H)-naphthalenone is now reduced to give 5-amino-3,4-dihydro-1(2H)-naphthalenone.
The transformation can be performed by hydrogenation in the presence of a hydrogenation catalyst. Practically all heterogeneous catalysts that are known as hydrogenation catalysts are suitable as hydrogenation catalysts for the process according to the invention (Rxc3x6mpp Lexikon Chemie; Georg Thieme Verlag, Stuttgart, 10th edition 1997, p. 1831, chapter xe2x80x9cHydrierungxe2x80x9d; Ullmann""s Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 5th edition 1989, vol. A13, chapter xe2x80x9cHydrogenation and Dehydrogenationxe2x80x9d, sub-chapter 1.2 xe2x80x9cCatalystsxe2x80x9d, p. 488). Preferred catalysts are the metals of groups 8-10 of the periodic table (G. J. Leigh [editor], Nomenclature of Inorganic Chemistry, Recommendations 1990, Blackwell Scientific Publications, Oxford, Chapter I-3.8.1 xe2x80x9cGroups of Elements in the Periodic Table and their Subdivision, p. 41-43), or copper and/or chromium on a suitable support with a metal content of 0.01 to 50 wt. %, preferably 0.1 to 20 wt. %, based on the total weight of the catalyst. Catalysts containing one or more of the above-mentioned metals can also be used. Preferred metals are, in particular, platinum, palladium and rhodium, platinum and palladium being particularly preferred. Other preferred catalysts are Raney nickel and supported nickel catalysts. The above-mentioned metals or their compounds can also be used in pure form as a solid. Palladium black and platinum black can be mentioned as examples of a metal in pure form.
The 5-amino-3,4-dihydro-1(2H)-naphthalenone produced in the reduction is then converted to 5-amino-3,4-dihydro-1-naphthylamine and/or 5-amino-3,4-dihydro-1(2H)-naphthylimine by reacting with ammonia, preferably in the presence of ammonium chloride.
The final aromatisation of 5-amino-3,4-dihydro-1-naphthylamine and/or the tautomeric 5-amino-3,4-dihydro-1(2H)-naphthylimine to 1,5-naphthalenediamine is performed as in step d) of the second preferred embodiment.
The conversion of the 5-amino-3,4-dihydro-1(2H)-naphthalenone to 5-amino-3,4-dihydro-1-naphthylamine and/or 5-amino-3,4-dihydro-1(2H)-naphthylimine and the subsequent aromatisation are preferably carried out in one reaction vessel.
All the reaction steps in this preferred embodiment of the process can be performed continuously or batchwise, e.g. in stirred vessel reactors or tubular reactors.
The processes according to the invention based on ortho-nitrotoluene and acrylonitrile can be illustrated in idealised form by the following reaction diagram: 
In a fifth preferred embodiment, the process for the production of 1,5-naphthalene-diamine contains the steps:
a) reaction of ortho-nitrotoluene with an acrylate or acrylamide to give 4-(2-nitrophenyl)butyrate or 4-(2-nitrophenyl)butyramide,
b) cyclisation of the butyrate or butyramide formed in step a) to give 5-nitro-3,4-dihydro-1(2H)-naphthalenone,
c) amination of the 5-nitro-3,4-dihydro-1(2H)-naphthalenone formed in step b) to give 5-nitro-3,4-dihydro-1-naphthylamine or the tautomeric 5-nitro-3,4-dihydro-1(2H)-naphthylimine,
d) aromatisation of the 5-nitro-3,4-dihydro-1-naphthylamine or the tautomeric 5-nitro-3,4-dihydro-1(2H)-naphthylimine formed in step c) to give 5-nitro-1-naphthylamine and/or 5-nitroso-1-naphthylamine,
e) hydrogenation of the 5-nitro-1-naphthylamine and/or 5-nitroso-1-naphthylamine formed in step d) to give 1,5-naphthalenediamine.
4-(2-Nitrophenyl)butyrates or 4-(2-nitrophenyl)butyramides are produced from ortho-nitrotoluene and acrylates or acrylamides preferably at temperatures of xe2x88x9210xc2x0 C. to 100xc2x0 C., It is particularly preferred to work at 20xc2x0 C. to 75xc2x0 C., especially preferably at temperatures of 30xc2x0 C. to 60xc2x0 C.
The reaction is performed with base catalysis. Oxides, hydroxides and carbonates of lithium, sodium, potassium, rubidium, caesium, magnesium, calcium, strontium, barium or aluminium, and mixtures thereof, can be used as bases. Sodium hydroxide and potassium hydroxide are particularly suitable. In a preferred embodiment, the aqueous solutions are used in combination with a phase transfer catalyst. These phase transfer catalysts are e.g. quaternary ammonium salts. Suitable ammonium compounds are tetraalkylammonium halides and hydrogen sulfates, such as tributylmethylammonium chloride, trioctylammonium chloride, tetrabutylammonium chloride or tetrabutylammonium hydrogen sulfate. The use of appropriate tetraalkyl- or tetraarylphosphonium salts, such as tetramethylphosphonium bromide and tetraphenyl-phosphonium bromide is also suitable, as is the use of solubility promoters, such as polyethylene glycol dimethyl ethers.
In principle, water and all organic solvents that are stable in bases are suitable as the solvents. Aromatic solvents, such as benzene, toluene, xylene, chlorobenzene, nitrobenzene or nitrotoluene, and also dimethyl sulfoxide, dimethyl formamide and aliphatic hydrocarbons, such as ligroin, cyclohexane, pentane, hexane, heptane or octane, are preferably used.
ortho-Nitrotoluene is particularly preferably used as educt and, at the same time, as solvent, and in an excess of ortho-nitrotoluene of 1 to 40 equivalents, especially 5 to 20 equivalents, based on the acrylic acid derivative.
The cyclisation of 4-(2-nitrophenyl)butyrates or 4-(2-nitrophenyl)butyramides to 5-nitro-3,4-dihydro-1(2H)-naphthalenone is performed in substance or in an inert solvent in the presence of strong acids. Suitable solvents are linear, branched or cyclic aliphatic hydrocarbons, such as ligroin or cyclohexane, pentane, hexane, heptane, octane and aromatic solvents such as nitrotoluene. It is preferred to operate in substance or in ortho-nitrotoluene.
Suitable acids are strong Lewis or Bronsted acids, such as e.g. aluminium chloride, boron trifluoride, sulfuric acid, phosphoric acid, polyphosphoric acid, phosphorus pentoxide, methanesulfonic acid, trifluoromethanesulfonic acid, trifluoroacetic acid or mixtures of antimony pentafluoride and fluorosulfuric acid. Mixtures of these acids can also be used. Sulfuric acid or phosphoric acid is preferably used.
The acid is generally used in 0.1 to 100 mole equivalents, based on 4-(2-nitrophenyl)-butyric acid derivative. Preferably, 0.5 to 20 equivalents are used, particularly preferably 1 to 10 equivalents.
The reaction is generally carried out at temperatures of 0xc2x0 C. to 150xc2x0 C., preferably between 60xc2x0 C. and 110xc2x0 C.
The amination of 5-nitro-3,4-dihydro-1(2H)-naphthalenone to the nitro imine and/or nitro enamine takes place by reaction with ammonia, preferably in the presence of ammonium salts such as ammonium chloride.
The aromatisation or dehydrogenation of the nitro enamine 5-nitro-3,4-dihydro-1-naphthylamine or of the nitro imine 5-nitro-3,4-dihydro-1(2H)-naphthylimine to 5-nitro-1-naphthylamine or 5-nitroso-1-naphthylamine or a mixture of the compounds is carried out, e.g. in an inert solvent, in the presence of a catalyst. In addition to the dehydrogenated product 5-nitro-1-naphthylamine, 5-nitroso-1-naphthylamine formally resulting from symproportionation can also be produced in the process. 1,5-Naphthalenediamine is also formed in traces. The products can be further processed in any mixing ratios. Suitable solvents are ammonia and linear, branched or cyclic aliphatic hydrocarbons such as ligroin or cyclohexane, and also acetonitrile and aromatic solvents such as benzene, toluene, xylene, nitrobenzene, nitrotoluene or chlorobenzene. The aromatisation can also be performed in the absence of a solvent.
Suitable catalysts are dehydrogenation catalysts, which are described in the literature (Rxc3x6mpp Lexikon Chemie; Georg Thieme Verlag, Stuttgart, 10th edition 1997, p. 891, chapter xe2x80x9cDehydrierungxe2x80x9d, 1st section; Ullmann""s Encyclopedia of Industrial Chemistry, VCH Verlagsgesellschaft mbH, Weinheim, 5th edition 1989, vol. A13, chapter xe2x80x9cHydrogenation and Dehydrogenationxe2x80x9d, sub-chapter 2, xe2x80x9cDehydrogenationxe2x80x9d, p. 494-497). These include the metals of groups 8-10 of the periodic table (G. J. Leigh [editor], Nomenclature of Inorganic Chemistry, Recommendations 1990, Blackwell Scientific Publications, Oxford, Chapter I-3.8.1 xe2x80x9cGroups of Elements in the Periodic Table and their Subdivision, p. 41-43), especially platinum, palladium, ruthenium and iridium, iron, cobalt, nickel and combinations thereof. The metals can also be used together with other metals, such as lanthanum, scandium, vanadium, chromium, molybdenum, tungsten, manganese, tin, zinc, copper, silver or indium. The above metals can be present as pure elements, as oxides, sulfides, halides, carbides or nitrides or can be used in combination with organic ligands. Suitable as ligands are hydrocarbon compounds with donor groups, such as e.g. amines, nitriles, phosphines, thiols, thioethers, alcohols, ethers or carboxylic acids. The catalysts are optionally applied to a support material. Suitable support materials are activated charcoal, aluminium oxide, silicon dioxide, zirconium oxide, zinc oxide or zeolites.
Work is optionally performed in the presence of an oxidising agent such as oxygen or air. The reaction is generally carried out at temperatures of 50xc2x0 C. to 250xc2x0 C., preferably at 100xc2x0 C. to 200xc2x0 C.
The subsequent hydrogenation of 5-nitro-1-naphthylamine or 5-nitroso-1-naphthyl-amine or a mixture of these compounds to 1,5-naphthalenediamine is performed as in step d) of the first preferred embodiment.
The process according to the invention based on ortho-nitrotoluene and acrylates and acrylamides can be illustrated in idealised form by the following reaction diagram: 
The 1,5-naphthalenediamine can be phosgenated to give 1,5-naphthalene diisocyanate by a method that is known per se (DE-A1-19 651 041).